THE COMPACT OPTION
C3 SuperMini
NZ$6.69 unsoldered
Compact USB-C board with an onboard antenna. The project describes SuperMini-class ESP32-C3 boards as its main target.
View at NZN ElectronicsAN EXPLORATION IN SMALL HARDWAREESP32-C3 · DNS AD BLOCKING
LESS NOISE, BY DESIGN
Tiny board.
Quieter internet.
TinyShield is an interactive showcase of M-Abozaid’s esp32-c3-adblock.
Explore how this open-source project turns a pocket-sized ESP32-C3 into a DNS filter for a properly configured home network.
Showcase and interactive explainer by Adrian
HARDWARE, ACTUAL SIZE: TINYESP32-C3 SuperMini
USB powered2.4 GHz Wi-Fi · 4 MB flash
A LITTLE BOARD WITH A VERY SPECIFIC JOBSCROLL TO EXPLORE
01 / THE IDEA
The best request is the one
you never have to load.
Before an app connects to a website, it usually asks DNS for the address. This board checks that domain against a blocklist. Known ad and tracker domains stop there. Other requests carry on.
Configure your network to use the board for DNS. Simply joining the board to Wi-Fi does not protect your other devices.
02 / FOLLOW THE SIGNAL
One request.
Three possible stories.
Choose a request and watch where it goes.
INTERACTIVE SIMULATION · NO LIVE NETWORK DATA
YOUR DEVICEsite.example.test
ESP32-C3Check the blocklist
UPSTREAM DNSResolve the address
ALLOWED
A clear path to the address.
This domain is not on the blocklist. The board forwards the DNS request upstream and returns the answer to your device.
Illustrative domains and simplified paths. This website does not inspect, filter, or connect to your network.
03 / SMALL BOARD. USEFUL CONTROLS.
The control room
stays at home.
The firmware serves a dashboard on your local network. See which devices are making requests, tune the list, and manage updates without reaching for a cable every time.
LOCAL DASHBOARD
http://c3adblock.localPlain HTTP on your trusted LAN. Do not expose the dashboard to the public internet. If the local name fails, use the board’s reserved IP address.
01
See the pattern
Per-client query and block counts help you understand what your devices are asking for.
02
Make the rules yours
Add blocked domains, upload a blocklist, and manage per-device DNS bans.
03
Keep the list fresh
Download a published blocklist over Wi-Fi, with a configurable weekly refresh schedule.
04
Update over the air
After the first USB flash, compatible dual-slot firmware builds support browser-based OTA updates.
04 / THE INTERESTING TRADEOFF
Four megabytes.
Choose your priorities.
Flash is shared by the firmware and the domain list. More list space means less room for convenient firmware updates.
~250kdomain capacity*
FIRMWARE OTA AVAILABLE
FIRMWARE OTA AVAILABLE
The current 4 MB partition file reserves two 1.3125 MB application slots and 1.3125 MB for the blocklist. Two app slots allow firmware OTA updates.
*Project-documented approximate limits, not performance measurements. The builder describes a roughly 100k default list; the older 141k example is not a guaranteed current count. Alternate layouts require a matching build and initial flash; this switch only explains the tradeoff.
05 / PICK YOUR TINY COMPUTER
Small footprint.
Real possibilities.
Three compact ESP32-C3 options.
Check the exact board and build before you buy.
ANOTHER TINY FORMAT
C3 Zero
NZ$7.49 listed sale price
A compact 4 MB ESP32-C3 board. Check pin mappings, flash settings, and board-specific build compatibility.
View at NZN ElectronicsTHE EXTERNAL-ANTENNA OPTION
XIAO ESP32C3
US$4.90 verified USD price
Seeed’s miniature 4 MB board uses an external antenna. Confirm the board profile and firmware compatibility before choosing it.
View at Seeed StudioPRICES CHECKED 7 OCT 2026
Different currencies; no exchange-rate comparison implied. Prices and stock can change. Shipping, tax treatment, cables, and accessories may vary. Product photographs belong to their respective retailers/manufacturers.
06 / FROM BOARD TO BLOCKLIST
A small project.
A deliberate setup.
You’ll need a compatible ESP32-C3 board, a USB data cable, 2.4 GHz Wi-Fi, and access to your router’s DNS settings.
Open the project guideThis is a guided overview. Use the repository’s current instructions and build files for your exact board.
- 01
Choose the matching build
Check the board profile and partition layout in the repository. Keep the normal dual-app layout if firmware OTA matters to you.
- 02
Flash once over USB
Follow the project’s PlatformIO instructions: configure secrets and strong dashboard/OTA passwords, generate the blocklist, and upload both firmware and filesystem. Use a USB data cable and the correct serial device.
- 03
Join your home Wi-Fi
Use the firmware’s captive setup portal to enter your Wi-Fi details. Reserve the board’s IP address in your router so its DNS address stays predictable.
- 04
Point DNS at the board
Set the DNS address distributed to clients by your router, or configure each client directly. Avoid an unfiltered alternate DNS server if you want consistent blocking. The firmware does not provide DHCP.
- 05
Check a client, then expand
Reconnect a test device or renew its network lease. Open the dashboard and confirm its DNS queries appear. Check private DNS, VPNs, and IPv6 settings if traffic bypasses the filter.
07 / KEEP EXPECTATIONS HONEST
Powerful.
Not magic.
DNS filtering is one useful layer. Understanding its boundaries is part of building it well.
Will it block every ad?
No. It blocks domains, not individual page elements. Ads served from the same domains as the content, including many YouTube ads, cannot be reliably separated this way. There is no cosmetic filtering.
Can a device bypass it?
Yes. Browser DNS-over-HTTPS, Android Private DNS, VPNs, hard-coded DNS, or alternate DNS addresses can bypass the board. Router and client settings determine coverage; connecting the board to Wi-Fi alone is not enough.
Does it support wildcards or regex?
No arbitrary wildcard or regex rules. However, the firmware also checks parent domains, so blocking a domain can cover its subdomains. Some simple Adblock-style domain rules are accepted by the list builder; cosmetic rules and complex patterns are skipped.
Is a device ban a complete internet kill switch?
No. The dashboard can refuse that client’s DNS queries, but a DNS-only block does not guarantee network isolation. Cached addresses, direct IP connections, or alternate resolvers may still work.
What if the board goes offline?
Devices relying on it may lose name resolution. Keep a note of your original DNS settings so you can restore them. An unfiltered fallback improves availability but can also let queries avoid the filter.
Is the dashboard safe to expose online?
Keep it on a trusted local network. The project serves the dashboard over HTTP; do not port-forward it to the internet. This showcase has no access to the board or your home network.
ONE BOARD. ONE DATA CABLE. A SMALL PLACE TO START.
NZ$10.18
in parts.
SuperMini · NZ$6.691 m USB data cable · NZ$3.49
Unsoldered board + USB-A to USB-C data cable. Prices checked 7 October 2026.
Delivery, USB power supply, and any needed USB adapter are extra.